1. Field of the Invention
The present invention relates to a vehicle and method for controlling brake system indicators.
2. Background Art
Many non-conventional vehicles, such as fuel cell vehicles (FCV's), hybrid electric vehicles (HEV's) and electric vehicles (EV's), use electro-hydraulic brake (EHB) systems with anti-lock braking systems (ABS) and regenerative braking systems (RBS). In these vehicles the EHB system may not provide brake pedal feedback to the vehicle operator when the ABS is active—i.e., when the ABS is in use. Without the brake pedal feedback, the vehicle operator may experience an unusual feel in the vehicle dynamics when the vehicle goes into an ABS event. This is in contrast to a vehicle having a mechanical ABS which provides pedal feedback to the vehicle operator when the ABS is active. This feedback makes the vehicle operator aware of the activity, and the vehicle operator knows not to pump the brake pedal to bring the vehicle to a stop.
Because EHB systems isolate the hydraulic circuit from the pedal, there are no brake pedal pulsations to provide feedback to notify the vehicle operator of an ABS action. The vehicle operator may experience unusual vehicle movements associated with the vehicle dynamics when the ABS is active. This change in feel may prompt the vehicle operator to pump the brake pedal, and thereby defeat the function of the ABS controller and diminish braking ability.
In addition, it may be desirable to provide a visual indication of the operating status of the vehicle's ABS or RBS. In this way, the vehicle operator will know that the braking system should be examined by a service technician. Because of the limited space available on vehicle instrument panels, it may also be desirable to combine two or more indicators in a single display window. This may be accomplished, for example, by displaying each indicator in a different color so the vehicle operator knows which information is being conveyed.
Therefore, a need exists for an instrument panel that includes indicators to provide feedback to a vehicle operator when an ABS event is occurring, and to indicate to the vehicle operator if an anomalous condition exists in the ABS or RBS.